Photonitrosation process using swirl-flow plasma arc radiation

ABSTRACT

Non-ionizing high intensity predominantly continuum light radiation having a source intensity of at least about 350 watts per square centimeter steradian when integrated throughout the entire spectral range of said continuum light radiation is used as the energy source in photochemical reactions. A convenient source of this non-ionizing high intensity predominantly continuum light radiation is a swirl-flow plasma arc radiation apparatus. Among the photochemical reactions that can be carried out, at unexpectedly faster rates and at higher conversions, are photoreduction reactions, photocycloaddition reactions, oxetane formation reactions, halogen additions, halogen substitutions, photonitrosation reactions, photosulfoxidation reactions, bisulfite addition reactions, and many other photochemical addition and substitution reactions.

United States Patent 1191 Osborn et al.

[ June 11-, 1974 PHOTONITROSATION PROCESS USING SWIRL-FLOW PLASMA ARC RADIATION Primary Examinerliien amin R. Padgett [75] Inventors: Clairborn Lee Osborn; Michael Ray Attorney Agent or Flrm prancls Fazlo Sandner; David John Trecker, all of Charleston, W. Va. 57 ABSTRACT [73] Asslgnee: Union Carbide Corporation New Non-ionizing high intensity predominantly continuum York light radiationhaving a source intensity of at least 22 Filed; 30 1971 about 350 watts per square centimeter steradian when integrated throughout the entire spectral range of said [21] Appl- N05 203,362 continuum light radiation is used as the energy source -in photochemical reactions. A convenient source of 52 us. 01. 204/162 XN, 204/162 R this non-ionizing high intensity predominantly comin- [51] Int. C|.....1 .1 B013 1/10 light radiation is a Swirl-flow Plasma are radiation [58] pick f Seal-chm" 2 58 R, 2 XN, 3 R, apparatus. Among the photochemical reactions that 204/162 R can be carried out, at unexpectedly faster rates and at higher conversions, are photoreduction reactions, 56] References Cited photocycloaddition reactions, oxetane formation reac- UNn-ED STATES PATENTS tions, halogen additions, halogen substitutions, photo- 3 479 264 H969 It t l 204/162 XN nitrosation reactions, photosulfoxidation reactions, bio e a sulfite addition reactions, and many other photochem- 3,498,895 3/l970 Streltsova 204/162 XN ical addition and Substitution reactions.

FOREIGN PATENTS OR APPLICATIONS 1,012,055 l2/1965 Great Britain 204/l62 XN 6 Clam, 4 D'awmg Fgures E so sou/r05 INTENSITY g 9 360 mm: cu sn" 10 E g l 60 E a g 5 5s 1 40 5 9 4- 1, 5 g 20 I E 10 B O l I I 1 1 l l 1 1 1 1 1 l 1 o 4000 e000 aooo IOOOO 12000 wavsuznsru- R 1- v PHOTONITROSATION PROCESS USING SWIRL-FLOW PLASMA ARC RADIATION BACKGROUND OF THE INVENTION The use of light energy sources such as ultraviolet light, visible light or infrared light to carryout chemical reactions is well known and several commercial products are produced by the use of such photochemical methods. However, they have been of limited application because of the low yields obtained, the long reaction times necessary, and the high costs associated with such processes.

SUMMARY OF THE INVENTION It has now been found that many of the known photochemical reactions can be carried out by the use of non-ionizing high intensity predominantly continuum light radiation that is artificially produced and has a source intensity of at least about 350 watts per square centimeter steradian when integrated throughout theentire spectral range of said continuum light radiation. This non-ionizing high intensity predominantly continuum light radiation has been found suitable for use in such photochemical reactions as photoreduction reactions, photocycloaddition-reactions, photochemical oxetane formation reactions, photochemical halogen addition reactions, photochemical halogen substitution reactions, photonitrosation reactions, photosulfoxidation reactions, photochemical bisulfite addition reactions, photochemical addition reactions such as the addition of oxygen, hydrogen halide, aldehyde, ketone, ether, lactam or lactone to olefins, and photochemical substitution reactions, all-as hereinafter more fully described.

Illustrative of the chemical reactions that have been indicated above and that have been carried out by the use of other photochemical means reference is made to US. Pat. Nos. 3,480,532, 3,472,749, 3,431,190, 3,090,739, 3,479,264, 3,507,909, 3,336,210, 3,342,714, 3,337,437, 3,459,648 and 3,498,895. These patents disclose photochemical reactions involving some of the classes of reactions referred to above; they are not to' be considered all-inclusive and acomplete listing of all patents in the field.

We have now found that the non-ionizing high intensity predominantly continuum light radiation emanat- 7 ing from a swirl-flow plasma are radiation source causes the above photochemical reactions to take place at an unobvious and unexpectedly much faster rate and to give higher yields of desired products. It has been found that in many instances the equivalent yield can be obtained in as little as one-tenth of the time that would be required using a conventional mercury ultraviolet lamp. The experimental data have shown many instances in which equivalent yields were obtained in a matter of several minutes as compared to periods up to several hours by prior processes.

In carrying out the photochemical reactions by the process of this invention, the compounds to be reacted are irradiated, neat or in solution, with or without the presence of a photosensitizer and/or activator, by exposure of the reaction mixture to the non-ionizing high intensity predominantly continuum light radiation emanating from a swirl-flow plasma arc. The compounds to be reacted can be in the form of solutions, emulsions,

dispersions, neat liquids, solids, gases, or as mixtures of liquids, solids and/or gases.

The irradiation or reaction time will vary depending upon the specific reaction system involved and the degree of conversion desired. Irradiation time generally varies from 0.01 second. to several hours, preferably from one second to three hours and more preferably from 10 seconds to about 20 minutes.

The distance of thereaction mixture undergoing .reaction from the plasmaarc. light source can vary from about 0.1 inch to about 25 feet, or more, the preferred distance is from one. inch to about five feet and more preferably from about three. inches to about three feet. The distance will be determined by many factors and, as is known, thefarther the reactants are located from a light energy source the longer will be the time required to carry out a particular reaction. Among the factors affecting the distance. are equipment design, desired reaction time, specificv compositions being reacted, the area of the reactor desired to be exposed to the light irradiation, the extent of reaction desired, and other factors known to those skilled. in photochemistry.

Temperature and pressure are'generally not critical variables in photochemical reactions. Usually ambient conditions are satisfactory and any rise in temperature or pressure accompanying the exposure of the reactants to the non-ionizing high intensity predominantly continuum light radiation can be accepted or readily controlled. The temperature can vary from about 30C. up to about C. or higher, with a range of from about l0C. to about 60C. preferred. The pressure can vary from subatmospheric to superatmospheric and can be from about 0.02 atmosphere to 50 atmospheres or higher. The particular temperature and pressure employed will vary with the specific reactant system being employed; this is known to those skilled in the art and they are adequately learned to handle the needed variations. I

In most instances an inert gas atmosphere is not required. However, the use of an inert gas atmosphere may be preferred to achieve optimum reaction and purity of product. The particular choice of inert gas, nitrogen, neon, helium, argon, carbon dioxide, or otherwise, will vary based on the specific reaction system undergoing irradiation.

As previously indicated, a photosensitizer may be present. Many compounds are known to be sensitizers. and many are usable in the practice of the present invention. It is also recognized by those skilled in the art that the number and kind of sensitizers known representsonly a small fraction of those materials which will be usable as sensitizers at some future date. Thus the specific materials described throughout this specification which may be utilized'as sensitizers in the practice of this invention are not to be considered as representing the complete class of sensitizers which are employable.

It has been discovered that any source of nonionizing light radiation emitting non-ionizing high intensity predominantly continuum light radiation con taining ultraviolet, visible and infrared radiation can be used to carry out the photochemical reactions. It was also foundthat by means of proper light filters, one can selectively screen out a portion of the non-ionizing light radiation emitted permitting only that wavelength portion desired to reach the material that is being treated.

The term non-ionizing high intensity predominantly continuum light radiation means continuum light radiation with a source intensity of at least 350 watts per square centimeter steradian when integrated throughout the entire spectral range of said continuum light radiation (about 1,000 kilowatts per square foot of source projected area) having only a minor part of the energy in peaks of bandwidths less than 100 A. units with a positive amount up to about 30 per cent of the light radiated having wavelengths shorter than 4,000 A. units and at least about 70 per cent but less than all of the light energy radiated having wavelengths longer than 4,000 A. units. This type of non-ionizing high intensity predominantly continuum light radiation is illustrated by the curves shown in FIGS. 1 to 3. These curves illustrate the non-ionizing high intensity predominantly continuum nature of the light radiation over the range of source intensity of from about 350 watts per square centimeter steradian to about 5,000 watts per square centimeter steradian. As is evident from the curves of FIGS. 1 to 3 the light radiated is predominantly continuum light with very little light emitted as line or peak radiation (band widths less than 100 A. units). It is also evident from FIGS. 1 to 3 that a positive amount up to about 30 per cent of the light radiated has wavelengths shorter than 4,000 A. and that at least about 70 per cent but less than all of the radiated light has wavelengths longer than 4,000 A. units.

This light radiation is derived from an artificial source that generates non-ionizing high intensity predominantly continuum light radiation with a source intensity of at least about 350 watts per square centimeter steradian when integrated throughout the entire spectral range of said continuum light radiation, as ab breviated by the term; watts cm sr; said nonionizing high intensity predominantly continuum artificial light radiation has at least about 70 per cent of the light radiated at a wavelength longer than 4,000 A. and a positive amount less than about 30 per cent of the light radiated having a wavelength shorter than 4,000 A., generally at least about 80 per cent of the light radiated has a wavelength longer than 4,000 A. and a positive amount less than about 20 per cent of the light radiated has a wavelength shorter than 4,000 A., and it has a source intensity that can vary from about 350 watts (about 1,000 kilowatts per square foot of source projected area) to about 5,000 watts (about 15,000 kilowatts per square foot of source projected area) or more per square centimeter steradian. A convenient source of non-ionizing high intensity predominantly continuum light radiation is a swirl-flow plasma are light radiation apparatus. The equipment for generating non-ionizing high intensity predominantly continuum light radiation by this means is known and available with many different forms thereof described in the literature. A highly efficient apparatus for obtaining non-ionizing high intensity predominantly continuum light radiation is the swirl-flow plasma arc radiation source described in US. Pat. No. 3,364,387. The apparatus or equipment necessary for generating the nonionizing continuum light radiation is not the subject of this invention and any source or apparatus capable of generating non-ionizing high intensity predominantly continuum light radiation can be used.

While any artificial source of generating non-ionizing high intensity predominantly continuum light radiation can be used, as previously indicated the swirl-flow plasma arc radiation apparatus is most convenient. Hence, this source will be used in this application as illustrative of a means for obtaining the non-ionizing high intensity predominantly continuum light radiation. Any apparatus that operates according to the known principles of the swirl-flow plasma arc radiation source can be used to produce the non-ionizing high intensity predominantly continuum light radiation useful in the processes of this invention. These apparatuses are often known by other terms but those skilled in the art recognize and know that they emit non-ionizing high intensity predominantly continuum light radiation. The source of radiation in a 50 kilowatt swirl-flow plasma arc radiation source is an are that is only about four inches long enclosed in a quartz envelope about 1.5 inches in diameter. This lamp or quartz envelope can be removed and refurbished and has an acceptable long lifetime. Further, a swirl-flow plasma arc radiation apparatus having a 250-kilowatt rating would be only about two or three times as large as a 50-kilowatt source. Another advantage of such radiation equipment is the absence of a need for expensive radiation shielding required to protect oneself from ionizing radiation with electron beam or atomic reactors. Precautions required for the artificial light sources useful in this invention include those needed to protect ones eyes from the intense light emitted and from the ultraviolet light emitted to prevent eye damage or inadvertent sunburn' effect on the body from the intensity of the light emitted.

It is to be noted that in the spectra of FIGS. 1 to 3 there is a continuum of radiation throughout the entire spectral range shown. This type of continuum radiation in the ultraviolet range has not heretofore been obtainable from the conventional commercial mercury arcs or lamps generally available for generating ultraviolet light. The previously known means for generating ultraviolet light produced light that shows a line or peak spectrum in the ultraviolet range, as exemplified by FIG. 4; it is not a continuum spectrum in the ultraviolet range. In a line spectrum the major portion of useable ultraviolet light is that portion at which the line or band in the spectrum forms a peak; in order for such energy to be useful the material or composition that is to be treated with ultraviolet radiation must be capable of absorbing at that particular wavelength range at which the peak appears. In the event the material or compostion does not have the ability to absorb at that particu- Y lar wavelength range there is little or no absorption or reaction. Thus, in the event the material or composition to be treated absorbs at a particular wavelength range in one of the valleys of the spectral curve there will be little or no reaction since there is little or no ultraviolet energy to adequately excite the system. With a non-ionizing high intensity predominantly continuum radiation, as is shown by FIGS. 1 to 3, there is a high intensity predominantly continuum radiation of ultraviolet energy across the entire ultraviolet wavelength range of the spectrum shown and there is generally sufficient ultraviolet energy generated at all useful ultraviolet wavelengths to enable one to carry out reactions responsive to ultraviolet radiation without the problem of selecting compounds that will absorb at peak wavelength bands only. With the non-ionizing high intensity predominantly continuum radiation now discovered one does not have the problem of being unable to react materials or compositions that absorb in the valley areas only since for all intents and purposes-such valleys do not exist in non-ionizing high intensity predominantly continuum radiation, the high intensity radiated light energy is essentially a continuum it is not in peak bands.

FIG. 1 is the light radiation curve from an 18 kilowatt argon swirl-flow plasma arc radiation source. The measured source intensity of the light was 360 watts per square centimeter steradian; about 8 per cent of the light had a wavelength shorter than 4,000 A. units and about 92 per cent of the light had a wavelength longer than 4,000 A. units. I

FIG. 2 is the light radiation from a 60 kilowatt argon swirl-flow plasma arc radiation source. The measured source intensity was about 2,300 watts per square centimeter steradian; about 10 per cent of the light had a wavelength shorter than 4,000 A. units and about 90 per cent of the light had a wavelength longer than 4,000 A. units.

FIG. 3 is the light radiation from a 71 kilowatt argon swirl-flow plasma arc radiation source. The measured source intensity was about 4,860 watts per square centimeter steradian; about 12 per cent of the light had a wavelength shorter than 4,000 A. units and about 88 per cent of thelight had a wavelength longer than 4,000 A. units.

Non-ionizing high intensity predominantly continuum light radiation as shown by FIGS. 1 to 3 is to be distinguished from low intensity ultraviolet radiation generated by commercially available low, medium and high pressure mercury arc ultraviolet lamps. These mercury arc lamps produce light emission which is primarily line or peak rather than continuum light. FIG. 4 is a typical curve for the light radiation from a mercury arc lamp. As shown in FIG. 4, a major part of the light appears in bands or peaks narrower than 100 A. units, and muchless than 70 per cent is emitted at wavelengths above 4,000 A. units.

As is known, non-ionizing high intensity predominantly continuum light radiation from a swirl-flow plasma arc radiation source is emitted from an arc generated between a pair of electrodes that are lined up axially and encased in a quartz cylinder. In one embodiment, a pair of concentric quartz cylinders between which cooling water or gas flows is used. A rare gas, such as argon, krypton, neon or xenon, introduced into the inner cylinder tangentially through inlets located at one end of the inner cylinder, creates a swirling flow or vortex which restricts the arc to a small diameter. An electrical potential applied across the electrodes causes a high density current to flow through the gas to generate a plasma composed of electrons, positively charged ions and neutral atoms. A plasma generated in the above gases produces non-ionizing high intensity predominantly continuum light radiation with diffuse maxima in the region of from about 3,500 to about 6,000.

The radiation source can also be used with reflectors or continuum light radiation according to the processes of this invention several classes of photochemical reactions will be discussed separately; with the understanding that the invented process is not necessarily restricted thereto. A. Photoreduction Reactions It is known to those skilled in the art that photoreduction reactions generally require the presence of two reactive parts, a light sensitive part in one of the reactants at whose site reduction 'takes place, and a second part capable in aiding reduction by supplying the required chemical element or elements for the reduction. These two parts may be present in the same chemical molecule or they may be present in different chemical molecules. Photochemical reduction reactions are known to take place quite readily when the light sensitive reactive site is a ketonic oxygen moiety.

A typical photoreduction reaction is illustrated by the reaction of benzophenone with benzohydrol to' pro- In this reaction the benzophenone is the light sensitive part. which undergoes reduction and the benzohydrol is the part aiding reduction by supplying the required elements therefor.

Another typical photoreduction reaction is the reaction of acetophenone with 2-propanol to produce 1,2- diphenyll ,2- butanediol:

NH: NH:

l I Q 02119 -1 1 Moira In this reaction paminobenzophenone functions as the light sensitive part which undergoes reduction and triethylamine is the part aiding the reduction.

The reaction of benzophenone with isobomeol to produce benzopinacol and camphor.

(IEO KA E IQKFO w hpofl Q Q In this reaction benzophenone is the light sensitive part which undergoes reduction and isoborneol is the part aiding the reduction.

Illustrative of suitable compounds which contain a light sensitive part at whose site reduction takes place one can mention acetone, 3-pentanone, diisopropyl ketone, dicyclohexyl ketone, dicyclohexen-3-yl ketone, benzophenone, 4,4-dimethoxybenzophenone, 4,4-dimethylbenzophenone, 4,4- dibromobenzophenone, 3,3-dimethylbenzophenone, 3,3-dimethoxybenzophenone, 4,4-dipyridyl ketone, 3,3-dipyridyl ketone, 2,2-dipyridyl ketone, acetophenone, Z-butanone, 2-methyl-3-pentanone, acetyl cyclohexane, 4-acetylcyclohexene, 4- methoxybenzophenone, 4-methylbenzophenone, 4- bromobenzophenone, 3-methylbenzophenone, 4-

(N,N-dimethylamino)-benzophenone, lacetonaphthone, methyl cyclopropylketone, 4-phenyl- 2-propanone, 2-acetyl-tetrahydropyran, 2-acetyl- 2H,3 H -dihydro- 4H-pyran, I-methoxy-Z-propanone, l-methylthio-2-propanone, 2-acetyl-2H,3H-dihydrothiophene, l-(N-methylamino)-2-propanone, 2- acetylpiperidine, 2-acetyll H,2H,3H,4II- tetrahydropyridine, 2-acetyll ,4-dioxane, 2 benzoylpyridine, 2-acetyl-1H,2H,3H,4H- tetrahydropyridine, 4-benzoylpyridine, 3- benzoylpyridine, 3-pyridyl 4-pyridyl ketone, 2,4-

' cal element or elements necessary for the photoreduction reaction one can mention methanol, ethanol, isopropanol, cyclopropylmethanol, 2-hydroxymethylbicyclo[2.2.l]heptane, diphenylmethanol, (4-methylphenyl )phenylmethanol, N-methylaminomethanol, 1,2-ethanediol, 1,2,3-propanetriol, l,3-diphenyl-2- propanol, ethanethiol, n-propanethiol, sec-butyl mercaptan, diethyl ether, diisopyopyl ether, ethyl benzyl ether, dibenzyl ether, diisobutyl ether, di-n-butyl sulfide, dibenzyl sulfide, benzyl n-butyl sulfide, dicyclohexyl sulfide, cyclohexanol, cyclopentanol, bicyclo- [2.2.1]heptan-2-ol, bicyclo[2.2.2]octan-2-ol, 4-hydroxytetrahydropyran, bicyclo[2.2. l ]hept-5-en-2- o1, cyclohexanethiol, bicyclo[2.2.l]heptane-Z-thiol, tetrahydropyran, 2H,3H-dihydro-4I-I-pyran, l ,4- dioxane, 1,3-dioxolane, morpholine, 1-thio-1,4- dioxane, 2,3-dihydro-p-isoxazine, 1,4-dithiane, l,3- .dithiolane, thiacyclohexane, n-hexane, n-octane, 2- octene, cyclopentane, cyclohexane, cyclododecane, cyclohexene, benzene, toluene, methylcyclopentane, cumene, ethylbenzene, n-bu tanol, ethyl formate, npropyl formate, tri-n-butylstannane, di(n-buty])cyclohexylstannane, diphenylisopropylstannane, n-butyldiphenylstannane, dibenzyl n-butylstannane, nbutylamine, diethylamine, triethylamine, N-ethylcyclohexylamine, N,N-dimethylaniline, aniline, N,N- diethylaniline, tribenzylamine, N,N-diethyl-1- naphthylamine, di-N,N-(p-tolyl)ethylamine, N- ethyldiethanolamine, diethanolamine, triethanolamine, piperidine, l,2,3,4-tetrahydropyridine, N methylpiperidine, N-methylmorpholine, N-methylperhydropyrazine, N-ethylmorpholine, pyrrolidine, N- phenylmorpholine, N-benzylmorpholine.

In some instances the two reactive parts, the light sensitive site at which reduction takes place and the site needed to aid reduction, are both present in the same compound. A typical illustration is the reaction of 2- hexanone to produce l,2-dimethylcyclobutanol. Illustrative of such suitable compounds one can mention Z-pentanone, n-propyl phenyl ketone, isobutyl phenyl ketone, 4-methoxy- 1 -phenyll -butanone, 3(B)acetoxy- A -pregnene-20-one, A -pregnene-3(B)0l-ZO-one, A- pregnen-3,2O-dione,A -androstane-3(,B)O l -l l-one, estrone,a-methoxyacetophenone, 01,4- dimethoxyacetophenone, l-methoxy-Z-propanone, 3- methoxy-Z-butanone, N-methylamino-2-propanone,a- (N-methylamino )acetophenone a-( N ,N- dimethylamino)acetophenone,a-(N,N-di-nbutylamino )acetophenone,a-( N,N-di-sec-butylamino acetophenone, l-methylthio-Z-butanone, 1- methylthio-2-propanone,a-methylthioacetophenone, cyclodecanone, cyclododecanone, 3-cyclodecenone, bicyclo[8.2. l ]-tridecan-l3-one, bicyclo[8.2.l ]tridec- Z-enel 3-one.

The photoreduction reactions are carried out by the processes of this invention by exposing the specific reaction system being employed to the non-ionizing high intensity predominantly continuum light radiation under the conditions hereinbefore defined and as more fully described in the operative examples appended hereto.

B. Photocycloaddition Reactions b. 1,3-butadiene to produce dimers c. B-nitrostyrene to yield dimers N: CH=CHNO Ph Ph d. cyclopentanone to produce dimers e. cyclohexene-3-one with l,l-dimethoxyethylene OCH;

OCH:

Another common photocycloaddition reaction involves cyclic ethylenically unsaturated compounds that are free of double bond conjugation. In this instance reaction occurs at the unsaturated bond sites to form new cycloadducts, as shown by the cycloaddition of bicyclohepteneto form the bicycloheptene dimer ad- COgH butadiene,

l0 non-ionizing high intensity predominantly continuum light radiation under the conditionshereinbefore defined. One can also include, if desired, a known photosensitizer to assist the reaction. Among the suitable photosensitizers one can mention acetophenone, pchloroacetophenone, m-chloroacetophenone, pmethylacetophenone, m-methylacetophenone, pmethoxyacetophenone, m-methoxyacetophenone, phenyl cyclopropyl ketone, dicyclopropyl ketone, acetone, diisopropyl ketone, isopropyl methyl ketone, methyl ethyl ketone, benzophenone, pmethylbenzophenone, m-methylbenzophenone, pmethoxybenzophenone, m-methoxybenzophenone, 4,4'-dimethylbenzophenone and 4,4'-dimethoxybenzophenone. These can be added in amounts as low as- 0.0l weight percent of the total weight of the reactants. When the compound is also used for solvent purposes, for example acetone, large excesses can be employed, as is known in the art.

It is known that the conjugated unsaturation in the compound is not necessarily restricted to carboncarbon conjugated unsaturation 0f the type C=CC=C; the conjugation can be the result of other types of unsaturation, for example ketonic unsaturation of the type Both of these are, for the purposes of this invention, considered conjugated olefinic structures.

Among the conjugated olefinic compounds that can be used in the photocycloaddition reaction and reacted with the ethylenically unsaturated compound by the process of this invention one can mention, 1,3- butadiene, l-cyano-l ,4-diphenyl-l ,3-butadiene, lcarboethoxy-l-cyan0-4-phenyl-1,3-butadiene, 1,1- bis(carbomethoxy)-4-phenyll ,3-butadiene, 2-methyl- 1,3-butadiene, 1,3-pentadiene, l-phenyl-l ,3- butadiene, 2-bromo-l ,3-butadiene, 2-ethoxy-l ,3- butadiene, l-ethoxy-1,3-butadiene, l-cyclohexyl-l ,3-

2-( 3-cyclohexenyl l ,3-butadiene, 2,3-diphenyll ,3-butadiene, 1,4-diphenyl-1 ,3- butadiene, l, l -d imethyll ,B-butadiene, 2-carbethoxy- 1,3-pentadiene, 1,2-dibromo-l ,B-butadiene, 2-amino- 1,3-butadiene, 2-nitro-l,3-butadiene, 2-N,N-diethylamino-l,3-butadiene, 2,4-pentadienoic acid, 1- nitrosol ,3 -butadiene, 2,3-dimethyl-l ,3-butadiene, l-vinyll -cyclopentene, l-methylene-3- cyclododecene B-( l-cyclohexenyl)styrene, 1 ,2- dimethylenecycloctane, 2-vinylbicyclo[ 2.2. 1 ]hept- Z-ene, 2-vinylbicyclo-[2.2.l ]hepta-2,5-diene, 2,3- dimethylenebicyclo[2.2.2]octane, l-( l -cyclohexenyl)cyclohexene, 3-vinyl-2H,3H-dihydro-4H-pyran,

3-methoxyl oxa-2,4-cycloheptadiene, cyclopentadiene, 2-phenyll ,3-cyclopentadiene, l-phenyl-l ,3- cyclohexadiene, benzene, ethylbenzene, bicyclo[4.2.2 ]-deca-2,4-diene, 3-methyll -oxa-2 ,4- cycloheptadiene, naphthalene, anthracene, 2H-pyran, 2-cyclohexen0ne, 2-cyclopentenone, 3,3,5-trimethyl- 2-cyclohexenone, 3-methyl-Z-cyclohexenone, 3-methyl-2-cyclopentenone, 2-phenyl-2-cyclohexenone, 4,4-dimethyl-2-cyclohexenone, Z-pyridone, N-methyl- 2-pyridone, 4,6-dimethyl-2pyrone, 4,5-diphenyl-2- pyrone, 2,3-dihydrol ,4-pyrone, bicyclo[3.2. 1.]oct-3- en-2one, bicyclo[3.2.O ]hept-3-en-2 one, 2,5-

] ,Z-diphenyll ,3-butadiene,

l-vinyl-l-cyclohexene,

group dimethoxyethylene, l, l-diethoxyethylene, 1,1- diphenylethylene, 1,2-diphenylethylene, 1,1- dichloroethylene, 1,1-dicyanoethylene, 2- methylpropene, l-chlorol ,2,2-trifluoroethylene, 2-

nitropropene, propenylcyclohexane,

benzyloxyethylene, isopropenyl propionate, vinyl acetate, methyl acrylate, l,1,l-trichloro-2-butene, phenyl vinyl ether, acetonitrile, acrylic acid, allylbenzene, 2- butene, dimethyl maleate, 1,2-diacetoxyethylene, ethyl 3-acetoxypropenoate, maleic acid, cinnamic acid, ethyl cinnamate, tetracyanoethylene, 1,2 -dicyanoethylene, maleamide, N,N'-dimethylmaleamide, 1,2- dinitroethylene, l,2-dibromo-l-propene, 1,2 -dibenzoyloxyethylene, B-nitrostyrene, ,B-methoxystyrene, cinnamamide; Z-methoxy-l-nitro-l-propene, l-cyano- Z-methoxyethylene, l,Z-dicyano-l-cyclohexene, lmethoxy-l-cyclohexene, I l-methyl-l-cyclopentene, l-methyl-l-cyclohexene, 1,3-cyclopentadiene, l-nitrol-cyclohexene, l-cyanol-cyclopentene, 1 -carboethoxy- 1 -cyclohexene, l-acetoxyl -cyclohexene, lbromol -cyclohexene, l-phenylcyclopentene, 2,3- dihydro-4H-pyran, cyclohexene, cyclopentene, bicyclo[2.2.llhept-2-ene, bicyclo[2.2.21oct-2-ene, bicyclo[2.2.l]hepta-2,5-diene, vinylene carbonate, 3- methyl-2,S-dioxa-3-cyclopentenone, maleic anhydride, maleimide, N-ethylmaleimide, l-phenylcyclohexene,

l-cyclohexen-1,Z-dicarboxylic anhydride, 1- cyclooctene-l ,2-dicarboxylic anhydride, N-ethyllcyclohexen l,2-dicarboximide, v

2,4-oxabicyclo[ 3.3.0" ]oct-A'- -en-3-one, 5-oxa-lcycloheptenl ,2-dicarboxylic anhydride. C. Photochemical Oxetane Formation In the photochemical reaction to form an oxetane compound it is generally necessary that two different reactive sites be present, one site being a carbonyl group and the other site beingan ethylenically unsaturated to which the carbonyl component adds to produc the oxetane structure:

1 bicyclo[2.2.1]heptan-Z-one,

l C M.

usually selected such that its triplet energy lies below that of the compound containing the ethylenically unsaturated group. This fact, as well as other conditions favoring oxetane formation, are well known to those skilled in theart and do not require repetition herein.

The photochemical oxetane reaction is carried out by exposing the reactants, either neat or in an inert organic solvent such as benzene, t-butyl alcohol, acetonitrile, carbon tetrachloride, etc., to the non-ionizing high intensity predominantly continuum light radiation under the conditions hereinbefore described. In many instances an excess of one or both of the reactants is used and this excess serves as the solvent. A photosensitizer can also be present.

Among thecarbonyl compounds that are useful in the oxetane reaction one can mention acetone, acetaldehyde, Z-butanone, cyclohexyl methyl ketone, 4- penten-2-one, 3-cyclohexen-l-yl ethyl ketone, acetophenone, benzophenone, l-acetylnaphthalene, naphthaldehyde, l-phenyl-2-butanone, 4,4-dimethylbenzophenone, 2-acetylthiophene, 2-benzoyl-l,4- dioxane, 2-acetyltetrahydropyran, 2-acetylfuran, 3- acetylpiperidine, 2-acetyl-l,4-dithiane, perfluoroacetone, acetyl bromide, cyclopropyl methyl ketone, crotonaldehyde, benzaldehyde, cinnamaldehyde, 2- acetylpyrazine, 2-acetylpyridine, 3-acetylpyridine, 4- acetylpyridine, 4-bromoacetophenone, 2- benzoylpyridine, 3-benzoylpyridine, 4-

benzoylpyridine, 4,4-dipyridyl ketone, 3,3-dipyridyl ketone, 4,4'-dibromobenzophenone, 4- methylbenzophenone, 4,4'-dimethoxybenzophenone, 2-benzoylperhydropyrazine, 3-benzoyl-5- ethylpyridine, dipyrazinyl ketone, acetyl cyanide, benzoyl cyanide, phenylglyoxylic acid, phenylglyoxylamide, 3-octyn-2-one, ethyl cya'noformate, phenyl glyoxylate, diethyl oxomalonate, benzil, benzoic acid, B-acetylstyrene oxide, cyclopentanone, cyclohexanone, 3-cyclohexenone, bicyclo[2.2.l]heptan-7-one,

bicyclo[2.2.21octan- 2-one, l-indanone, bicyclo[4.4.0" ]-decan-2-one, ltetralone, fluorenone, tetrahydro-l,4-pyrone, 1,4- benZoquinone, chloranil, 4-pyridone, l ,4- naphthaquinone, acridan-9-one, xanthone, thioxanthone, e-caprolactone, e-caprolactam.

Among the ethylenically unsaturated organic compounds that react with the carbonyl compounds one can mention Z-methylpropene, Z-pentene, 1,1- diphenylethylene, 2-cyclohexylpropene, vinylcyclopropane, 2-( l-cyclohexenyl)propene, chlorotrifluoroethylene, stilbene, fumaronitrile, tetramethylethylene, vinyl chloride, styrene, l-nitro-l-propene, ethylene, methylenecyclopentane, methylenecyclohexane,

2-methylenebicyclo[2.2. l ]hexane, 2- ethylidenebicyclo/2.2.1 ]hexane, 5- ethylidinebicyclo[2.2. l ]hex-Z-ene, 9- methylenefluorene, 4-methylene-4H-pyran, 4 methylene-l ,S-cyclohexadienone, 9-

methylenexanthene, 9-methylene-lO-thioxanthene, cyclopropylidene cyclopropane, cyclohexylidene cyclohexane, cyclopropylidene cyclohexane, cyclopropene, cyclohexene, l-methyll -cyclohexene, 7-carboxybicy- 13 clo[2.2. l lhept-2-ene, l-phenyl- 1 -cyclopentene, cycloheptene, cyclooctene, phenanthrene, cyclobutene, 2,3- dihydro-4H-pyran, 1,4-dioxene, furan, 4H-pyran, bicyclo[2.2. l ]hepta-2,5-diene, bicyclo[2.2. l ]hept-2-ene, 7-oxabicyclo[2.2. l lhept-Z-ene, bicyclo[2.2.21oct- Z-ene, l,4-benzoquinone, l,4-dithia-2-cyclohexene, bicyclo-[4.4.0- ]dec-A- -ene, thiophene, benzofuran, benzothiophene, Z-methylfuran, 1,2;5,6-dibenzo-7- oxa-l, 3,5-cycloheptatriene, l,3-dioxole, maleic anhydride, vinylene carbonate, maleimide, 2-oxo-2H,3H- imidazole, 4-hydroxy-3-butenoic'acid a-lactone, thymine, indene. I

Illustrative thereof is the production of oxetanes by the following reactions:

Halogen Addition wT The photochemical halogen addition reaction is known to take place quite readily by the addition of a This reaction can be illustrated by the equation:

when the unsaturated compound'contains ethylenic unsaturation. The reaction is carried out by bubbling the halogen through the unsaturated compound, either neat or in solution, while exposing the reaction mixture to the non-ionizing high intensity predominantly continuum light radiation under the reaction conditions hereinbefore described. One can also, if desired, add the halogen in liquid form to the reaction mixture.

Illustrative of suitable unsaturated compounds one can mention acetylene, 2-butyne, cyclohexylacetylene, 3-cyclohexenl -ylacetylene, diph enylacetylene, phenylacetylene, 3,3.3-trichloropropyne. l-methoxy-lpropyne, cyclooctyne, cyclodecyne, ethylene, lpropene, vinylcyclopropane, Z-butene, 1,3-butadiene, styrene, stilbene, 3-buten-2-one, acrylonitrile, acryloylbenzene, l-butene, 3,3-dichloro-l-propene, tetrachloroethylene, l,2-dichloroethylene, l, l ,2,3,4,4-hexachlorol ,3-butadiene, vinylcyclohexane, 2-vinyltetrahydropyran, isoprene, vinyl chloride, nitroethylene, ethoxyethylene, methylenecyclohexane, methylenecyclopentane, 2-methylenebicyclo-[2.2.llheptane, 2- ethylidenebicyclo[ 2.2.1 lheptane, methylenecyclooctane, l,2,3,4,7,7-hexachloro-5-methylene-2- norbomene, 9-methylenefluorene, 9- methylenexanthene, l-methylene-2,2,3,3,4,4,5,5-octachlorocyclopentane, benzylidenecyclohexane, acetonylidenecyclohexane, cyclopentene, cyclohexene, l,3-cyclohexadiene, benzene, l,5cyclooctadiene, bicyclo[2.2. l ]hept-2-ene, bicyclo[2.2. l ]hepta-2,5- diene, bicyclo[2.2.2]oct-2-ene, bicyclo[2.2.21octa- 2,5-diene, 4I-I-pyran, 2,3-dihydro-4H-pyran, 2,3- dihydrofuran, phenanthrene, ZI-I-pyran, thiophene, maleic anhydride, 2,3-dimethylmaleic anhydride, 2-

-cyclohexenl ,4-dione, 2-cyclopenten- 1 ,4-dione, l ,3-

dioxole, vinyl'ene carbonate, 5-hydroxy-4-pentenoic acid fi-lactone, lH-heptafluorocyclopentenel,pyridine, phthalic anhydride, dimethyl terephthalate, 6-chlorotoluene-2-sulfinyl chloride, tetralin bicyclo[4.4.0" ]decA" -ene, benzofuran, l-cyclohexen- 1,2-dicarboxylic anhydride, naphthalene, anthracene, etc.

In the following table a few photochemical halogen addition reactions are listed that are illustrative of this invention:

Product Halogen Olefin Cl CHz=CHg ClCH CI-l CI CI CHECH -CICH=CHCI and CI CHCHCl chlorine methyl vinylether methyl dichloroethyl ether bromine cyclohexene dibromocyclohexane bromine maleic anhydride dibromomaleic Y anhydride E. Photochemical Halogen Substitution In the halogen substitution reaction a halogen,such

as one of those previously described, is substituted into the molecule and generally would replace a hydrogen atom. This reaction is also well known and proceeds according to the general reaction:

C1 RH RC1 HCl wherein RH is an organic compound or hydrogen. In our process, the reaction mixture is exposed to the nonionizing high intensity predominantly continuum light radiation under the reaction conditions hereinbefore described. At the completion of the reaction the halogenated compound is recovered by conventional means.

Illustrative of compounds of different types which can be used and which undergo the halogen substitution reaction one can mention hydrogen, methane, ethane, propane, cyclohexane, cyclopentane, bicyclo[2.2.l ]-heptane, bicyclo[2.2.1lhept-Z-ene, bicyclo [2.2.l] -hepta-2,5-diene, l-propene, cyclopentene, cyclohexene, acetylene, propyne, cyclooctyne, 1,3- butadiene, tetrahydropyran, tetrahydrofuran, dioxane, toluene, a-chlorotoluene, a, a-dichlorotoluene, 4-chlorotoluene, ethylbenzene, o-xylene, ethyl methyl ether, piperidine, 1,4-dithiane, Z-butanone, 1,4- dioxane, benzoic acid, acetic acid, H l,l ,ltrichloroacetone, e-caprolactam, nitrosocyclohexane, l,2,2,-trichloropropane, nitroethane, phenylacetic acid, l,3-dioxolan-2-on'e, 4-methyll ,3-dioxolan-2-one, N,N-dimethylacetamide, 2,3-dichlorobutane, B-chloropropionitrile, dichloroacetyl chloride 1,]- diehloroethane, ethylene oxide, styrene oxide, ptoluonitrile, 2-fluoropropane, monochloromethylphosphonic dichloride, 2-nitropropane, acetophenone, ptoluic acid, trifluoroacetaldehyde, p-xylene, ndodecane, etc.

The following table sets forth a few halogen substitution reactions that are illustrative of reactions that can be carried out by the process of this invention:

chlorine cyclohexane chlorocyclohexane chlorine cthylbenzene chioroethylbenzene chlorine methyl ethyl ether chloromethyl ethyl ether andchloroethyl methyl ether bromine acetophenone alpha-bromoacetophenone bromine methane mixture of bromomcthanes F. Photonitrosation Reactions The photonitrosation reaction is one in which an organic molecule is reacted with a nitrosating agent to produce an oxime or nitroso compound. The nitrosating agents useful are nitrosyl chloride; a mixture of nitrosyl chloride and hydrogen chloride; a mixture of nitrogen oxide, chlorine and hydrogen chloride; a mixture of nitrogen oxide, and chlorine; a mixture of nitrogen oxide, nitrogen peroxide and hydrogen chloride; a mixture of nitrogen oxide, oxygen and hydrogen chloride; or a mixture of nitrosylsulfuric acid and hydrogen chloride.

In the photonitrosation reaction, the nitrosating agent is reacted with an organic compound to produce the nitroso compound, as follows:

in which (NO, Y) is the nitrosating agent. In many instances the nitroso compound will rearrange to the oxime, as indicated below The reaction is carried out by exposing the mixture of nitrosating agent and organic compound to the nonionizing high intensity predominantly continuum light radiation under the conditions hereinbefore described. Generally the reaction is carried out in the liquid phase using the organic compound as the solvent; however, one can, if desired, use a different inert solvent.

Among the compounds that will react with the nitrosating agents one can mention ethane, propane, cyclopentane, eyclohexane, cycloheptane, cyclobutane,

cyclooctane. cyclodecane, cyclododecane, bicycl[2.2. l ]-heptane, bicyclo[2.2.2]octane, cyclohex ane. 2-chloropentane, chlorocyclohexane, chlorocyclopentane, toluene, ethylbenzene, 2- chlorobicyclo[2.2. l ]heptane, tetrahydropyran, l,4- dioxane, nitrocyclohexane, nitrosocyclohexane, cyclohexanone oxime, p-toluic acid, l-chloro-lnitrosocyclohexane. etc. G. Photosulfoxidation Reactions The production of organic sulfonic acid compounds by the reaction of an organic compound, sulfur dioxide and air or oxygen is known. These compounds can now be prepared in high yield by the process of the instant invention by the irradiation of the reactive mixture with the non-ionizing high intensity predominantly continuum light radiation emanating from a plasma arc source under the conditions previously described. This reaction is quite complex and has been studied extens'ively. A simple mechanistic representation is shown by the equation:

Ordinarily gaseous sulfur dioxide is employed, but the liquid form can be used under proper reaction conditions. Any of the organic compounds known to form sulfonic acid derivatives can be reacted by the process of the instant invention.

Illustrative of compounds which will undergo the photosulfoxidation reaction one can mention n-hexane, n-octane, n-decane, n-dodecane, n-tetradecane, nhexadecane, cyclopentane, .cyclohexane, cyclooctane, cyclododecane, cyclodecane, bicyclo[2.2.l]heptane, bicyclo[2.2.2]octane, l-dodecyne, chlorocyclohexane, n-octylbenzene, n-hcxylbenzene, tetrahydropyran, l ,4- dioxane, methyl n-dodecyl ether, phenyl nundecanoate, cyclohexanesulfonic acid, 2-dodecanesulfonic acid, l-tetradecanol.

H. Photochemical Bisulfite Addition Reactions The addition of bisulfites to ethylenically unsaturated compounds to produce sulfonic acid compounds is also known. This reaction can now be carried out by the method of the instant invention using any of the bisulfite salts previously known to be useful. The reaction generally starts out as a two phase system and as the reaction proceeds it becomes a single phase system.

In the process of this invention a mixture of a bisulfite and an unsaturated organic compound is exposed to the non-ionizing high intensity predominantly continuum light radiation emanating from a plasma are light source under the conditions previously described. The reaction can be represented by the equation:

As is known, promoters such as'acetone, methyl ethyl ketonc, diethyl ketonc, cyclohexanone, cyclopentanone, methyl tert-bulyl ketonc, acctophenone, benzophenone, phenyl ethyl ketone, benzene, naphthalene, biphenyl, anthracene, chrysene, pyrene, phenanthrene, naphthacene, eosin, fluorescein, rose bengal, methylene blue and the like, can be used in this reaction if desired. When used they are generally present at a concentration up to about 20 percent by weight of the reaction mixture.

Among the unsaturated organic compounds which can be used in the bisulfite addition reaction one can mention l-butene, l-hexene, l-heptene, l-octene, 1- decene, l-dodecene, l-tetradecene, l-hexadecene, vinylcyclohexane, vinylcyclopentane, 3-dodecene, 4- vinylcyclohexene, styrene, 9-decen-l-yne, 4- methylstyrene, decyl vinyl ether, IO-undecen-l-ol, l0- phenyldecl -ene, methylenecyclohexene, methylenecyclopentane, Z-methylenebicyclo- [2.2.1]heptane, 2-ethylidenebicyclo[2.2.l ]heptane, methylenecyclodecane, benzylidenecyclohexane, cyclohexylidenecyclohexane, cyclohexene, cyclopentene, cyclooctene, l,5-cyclooctadiene, bicyclo[2.2.l- ]hepta-2,5-diene, bicyclo[2.2.l]hept-2-ene, bicyclo[2.2.2]-oct-2-ene, bicyclo[4.4.0" ]dec-A" -ene, l,4-dioxene, 4H-pyran, 6-hydroxy-5-hexenoic acid e-lactone, coumarin, l-propyne, l-tridecyne, cyclohexylacetylene, l-dodecen lO-yne, phenylacetylene, benzylacetylene, dodecyne.

I. Miscellaneous Photochemical Addition and Substitution Reactions In this category will be found listed several other classes of reactions known to occur by photochemical means that can be carried out by the processes of this invention.

a. The addition of oxygen to an olefinically unsaturated compound such as butadiene:

, b. Another category is the addition of a hydrogen halide to an olefinically unsaturated compound:

c. Halogenated alkanes can be added to an olefinically unsaturated compound according to the equation:

d. The addition of analcohol or thiol to an olefinically unsaturated compound to produce an hydroxyl ketone, or keto ether, or thiol compound as illustrated by the following general equations:

e. A photochemical addition of an aldehyde or ketone to an olefinically unsaturated compound as illustrated generally by the equations:

f. A photochemical addition of a lactam or lactone to an olefinically unsaturated compound in the presence of a photosensitizer containing a carbonyl group such as acetone, benzophenone and acetophenone, as shown by the equation:

g. The photochemical addition of an ether to an olefinically unsaturated compound in the presence of a photosensitizer such as described above:

h. The photochemical substitution in an aromatic compound of an amine as represented by the reaction:

ester with an alcohol to produce an ether compound and free an acid compound, as shown by the reaction:

cmooon onion BCOOH OCH: CH;

j. The photochemical displacement reaction wherein a substituent on an aromatic ring is replaced by a different substituent,- as illustrated by the equations:

N02 OH Q OH" N01" OCH; OCH:

2 Clz 2 2H As can be seen from the above description the process of the instant invention'can be used to carry out any of the known photochemical reactions. In each instance, the ratios of reactants are those known to those skilled in the art and thus elaborate detailed descriptions are not necessary.

The following examples serve to further describe the processes of this invention.

EXAMPLE 1 A series of experiments was carried out using varying concentrations of reactants. In this series a solution of benzophenone and benzohydrol in benzene was placed in pyrex tubes inches long and 0.6 inch in diameter. The solutions were degassed wit-h a stream of nitrogen and the tubes then sealed. The irradiation was carried out with the sealed tubes placed on a rotating carriage located about three inches interior of a circle of 16 Rayonet RPR-350O mercury lamps, each lamp rated at about 1.6 watts. The circle of mercury lamps had a diameter of about 12 inches. This equipment is available commercially as the Rayonet RPR-lOO Reactor from the Southern New England Ultraviolet Co., Middletown, Conn. The irradiation was carried out for 600 seconds at ambient reactor temperature and the reaction was then arbitrarily stopped and conversion to benzopinacol was determined by ultraviolet spectroscopic analysis. These results are tabulated below:

From this data it is seen that the average conversion is about 31 mole per cent over a 600 second or minute reaction period using conventional, commercially available mercury ultraviolet lamps.

EXAMPLE 2 A series of experiments was carried out using varying concentrations of reactants: In this series a solution of benzophenone and benzophydrol in benzene was placed in pyrex tubes 5 inches long and 0.6 inch in di ameter. The solutions were degassed with a stream of nitrogen and the tubes then sealed. The irradiation was carried out by immersing the tubes in an ice bath and exposing them to the irradiation from a 550 watt mercury lamp at a distance of 9 inches from the lamp. The temperature of the contents of the tubes was not measured during the reaction. The irradiation time was varied for arbitrarily selected periods and then the tubes were removed and the contents analyzed for conversion to benzopinacol. These results are tabulated below:

Benzophenone Benzohydrol vTime Conversion to molar conc. molar conc. sec. benzopinacol.

0.1 0.375 600 18 0.2 0.375 600 18 Av. 18 0.1 0.375 900 0.2 0.375 900 24 Av. 24.5

EXAMPLE 3 Three series of experiments were carried out using varying concentrations of reactants. In these series solutions of benzophenone and benzohydrol in benzene were placed in pyrex tubes 5 inches long and 0.6 inches in diameter. The solutions were degassed with a stream of nitrogen and the tubes were sealed. The tubes were immersed in an ice bath and then exposed to the nonionizing high intensity predominantly continuum light radiation emanating from a SO-kilowatt plasma are light source at a distance of 21 inches from the light source. The irradiation was carried out for seconds; the temperature of the tube contents during the reaction was not measured. The reaction was arbitrarily halted and the tubes were removed and the contents analyzed for conversion to the benzopinacol. The results are tabulated below:

It was found that high conversions, up to 33 mole per cent, were obtainable in periods as short as 70 seconds. Such conversions were not affected by variation of the benzophenone concentration in the reaction mixture as seen from the results obtained in Series I. It was also found that varying the concentration of the benzohydrol did have an effect on conversion and that conversion decreased as the benzohydrol concentration was decreased, Series II and Ill. Nevertheless, in all instances, the conversion to benzopinacol was at a much faster rate than could be achieved by the use of conventional, commercially available ultraviolet lamps, as shown by a comparison of the results in Example 3 with the data of Examples 1 and 2. In Examples 1 and 2 the irradiation period was 600 seconds or 900 seconds, whereas in Example 3 the irradiation period was only 70 seconds. It is also to be noted that higher yields were obtained in the shorter time with the reactants located at a further distance from the light source in Example 3 than they were located in Examples 1 and 2.

EXAMPLE 4 A 20 ml. portion of a benzene solution that was 0.5 molar in maleic anhydride and 0.1 molar in benzophenone was charged to a pyrex tube, purged with nitrogen and sealed. Separate series of tubes were prepared and irradiated by the procedures described in Examples 2 and 3. Series B, exposed to the conventional mercury ultraviolet lamp was irradiated for minutes or two hours. Series A, exposed to the non-ionizing high intensity predominantly continuum light radiation emanating from the plasma arc was irradiated for only 6 minutes. These were arbitrarily selected periods for convenience in an attempt to obtain approximately equal conversions. In both instances the product produced was the adduct tricyclo[4.2.2.0 ]dec-9-ene-3,4,7,8- tetracarboxylic acid dianhydride, which was filtered, dried and weighed. The data, tabulated below, show that when the reaction was carried out by exposing the reactants to the non-ionizing high intensity predominantly continuum light radiation the yield would be much higher for an equivalent reaction period. This is a completely unexpected and unobvious result. The data show that in 6 minutes the average conversion to product was 0.039 gram when the reaction mixture was exposed at a distance of 21 inches to the non-ionizing high intensity predominantly continuum light radiation emanating .from the plasma arc radiation source. Whereas, after 120 minutes, or a period times longer, the average conversion to desired product was only 0.051 gram, or 30 percent more, when the reac tion mixture was exposed at a distance of only 9 inches to mercury lamp ultraviolet irradiation; that 0.039 gram could be produced in 6 minutes versus 0.051 gram in 120 minutes is completely unexpected. The identity of the product was confirmed by comparison of its infrared spectrum with that of an authentic sample.

EXAMPLE 5 A benzene solution was that 5 molar in norbomene and 0.5 molar in acetophenone was prepared and 20 ml. portions were placed in pyrex tubes; these were then purged with nitrogen and sealed. Separate series of tubes were prepared and irradiated by the two procedures used in Example 4. In both instances an 88:12 mixture of the isomeric dimers endo-trans-exopentacyclo[ 8.2. l. l .0 0 1tetradecane and exotrans-exo-pentacyclo[ 8.2. l l" .0 .0 ]tetradecane was produced. Again, the data tabulated below shows the unexpected and unobvious higher yields achieved by the use of the plasma arc (Series A), as noted by an average yield of 0.0439 gram of the dimers product in 6 minutes when the reaction was carried out by exposure to the non-ionizing high intensity predominantly continuum light radiation emanating from a plasma arc radiation source and an average yield of only 0.0614 gram of the dimers after 120 minutes (20 times as long a period) when using the conventional ultraviolet mer- 6 cury lamp (Series B). The yields were determined by vapor phase chromatographic analysis.

Irradiation time, min. Yield, g.

Series A Run A 6 0.0432 8 6 0.0414 C 6 0.0470 Av. 0.0439

Series B A Control Run A 0.0583 B 120 0.0677 C 120 0.0583 Av. 0.06l4

EXAMPLE 6 A benzene solution that was 0.2 molar in norbomene and 0.2 molar in benzophenone was prepared and 20 ml. portions were placed in pyrex tubes; these were then purged with nitrogen and sealed. Separate series of tubes were prepared and irradiated by the procedures described in Example 4. The oxetane, 4,4- diphenyl-3-oxatricyclo[4.2.l.0 ]nonane was produced as determined by vapor phase chromatographic analysis. The data shows that after 6 minutes of exposure to the non-ionizing high intensity predominantly continuum light radiation ata distance of 21 inches from the plasma arc radiation source that an average yield of 0.0635 gram of the oxetane was obtained (Series A). Whereas, it required 120 minutes of exposure to the ultraviolet light radiation at a distance of 9 inches to obtain a slightly lower average yield of 0.0626 gram when the reaction was carried out by exposing the reactants to the mercury lamp (Series B). The fact that a slightly higher average yield is obtained in l/20th of the time by the process of this invention was a completely unexpected and unobvious finding.

Following procedures similar to those described in Example 4, 20 ml. portions of a benzene solution that was 0.2 molar in norbomene and 0.2 molar in 3 benzoylpyridine were exposed to the non-ionizing high intensity predominantly continuum light radiation ema- 5 nating from a SO-kilowatt argon plasma arc radiation source (Series A) and to the ultraviolet light emanating from a conventional 550-watt mercury lamp (Series B) to produce the oxetane, 4-(3-pyridyl)-4-phenyl-3-oxatricyclo[4.2.1.0 ]nonane. The average yield of oxetane was 0.0618 gram after an exposure time of only 6 minutes to the non-ionizing high intensity predominantly continuum light radiation at a distance of 21 inches from the plasma are light source; whereas, the average yield of oxetane was only 0.0596 gram after irradiating for 120 minutes at a distance of nine inches from the mercury lamp. The higher yield obtained in 1/20 the reaction time at a distance 2 /3 time as far from the light source was completely unexpected and unobvious. Theresults are set forth in the following table:

A solution containing 1 ml. of benzene and 99 ml. of carbon tetrachloride was treated at room temperature with chlorine gas at a flow rate of 180 ml. of chlorine per minute for 15 minutes. Fifty ml. portions of the solution were sealed in pyrex tubes and subjected to irradiation. Series A was exposed to the non-ionizing high intensity predominantly continuum light radiation emanating from a 50 kilowatt argon swirl-flow plasma arc for 2 minutes as described in Example 3. Series B of the sealed tubes was exposed to ultraviolet light for 15 minutes using the equipment described in Example 1. The hexachlorocyclohexane produced was recovered by purging the reaction mixtures with nitrogen for 20 minutes and then vacuum distilling to remove the solvent. The yield was determined by vapor phase chromatographic analysis; the average yield in Series A was 1.63 grams in 2 minutes whereas the average yield in Series B was only 1.5 grams after 15' minutes of reaction time; this was a completely unexpected finding, that higher yields were obtained in Series A. The results are tabulated below:

per minute for minutes. Fifty ml. portions of the solution were sealed in pyrex tubes and irradiated. Series A was exposed to the non-ionizing high intensity predominantly continuum light radiation emanating from a 50-kilowatt argon swirl-flow plasma are for 2 minutes as described in Example 3. Series B was exposed to-ultraviolet light for 15 minutes as described in Example 1. The a, a, a-trichloromethylbenzene produced was recovered by purging the contents with nitrogen for minutes and then vacuum distilling to remove the solvent. The yield was determined by vapor phase chromatographic analysis; the average yield in Series A was 0.471 grams in 2 minutes, whereas the averageyield in Series B was 0.573 grams after 15 minutes of reaction A solution containing 5 ml. of toluene and 495 ml. of

time. The high yield obtained in Series A after only 2 minutes as compared to the yield in Series B after 15 minutes was a completely unexpected and unobvious finding. The results are tabulated below:

Irradiation 7 time, min. Yield.g.

Series A Run A 2 0.408 B 2 0.533 C p 2 0.472 Av. 0.471

Series B Control Run A 15 0.533 B 15' 0.589 C 15 0.597 Av. 0.573

EXAMPLE 10 7 One hundred ml. portions of cyclohexane were treated with hydrogen chloride gas at room temperature at a gas flow rate of 461 ml. per minute for various periods of time. Then, nitrosyl chloride was introduced at a gas flow rate of 126 ml. per minute while continuing the flow of hydrogen chloride at 461 ml. per minute. Then portions of the solutions in sealed pyrex tubes were exposed to the non-ionizing high intensity predominantly continuum light radiation emanating from a 50-kilowatt argon plasma are for the times indicated by the procedure described in Example 3'. After irradiation, the unreacted cyclohexane was removed by vacuum distillation. The residue was dissolved in l N sodium bicarbonate and extracted with ether. The ether extracts were combined, washed with water and then the ether was flashed off. The residual cyclohexanone oxime was analyzed by vapor phase chromatography. The data and yields for the plasma arc irradiation are set forth below:

Gas Treatment, min.

Irradiation 1101 NOC1+ 1-1c1 time, min. Yield, g.

20 20 1 0.0888 20 20 1 0.0470 20 20 1 0.052s Av. 0.0629

For comparison, cyclohexane was treated with hydrogen chloride and nitrosyl chloride in the same manner described above and 20 ml. portions were sealed in pyrex test tubes and irradiated with ultraviolet light from a mercury lamp by the procedure described in Example 2. Thecyclohexanone oxime was recovered as described above and the data and yields are set forth below:

The data shows that cyclohexane treated with hydrogen chloride and a mixture of hydrogen chloride plus nitrosyl chloride for minute periods each gave an average yield of 0.1 gram of cyclohexanone oxime in l minute by the process of this invention and that the average yield was only 41.5 per cent higher when it was irradiated for a period 20 times longer, 20 minutes. with the mercury ultraviolet lamp. Cyclohexane treated with said gases for 20 minute periods each, produced an average yield of 0.0629 gram after 1 minute and 0.1303 gram after 2.5 minutes irradiation by the process of this invention; whereas, irradiation with the mercury lamp for 10 minutes produced only 0.00791 gram. for minutes only 0.0385 and only 0.2203 gram after minutes. Finally, cyclohexane treated with the gases for 30 minute periods each, produced an average yield of 0.2072 gram of the cyclohexanone oxime in 2.5 minutes by the process of this invention and only 0.1778 gram thereof in 20 minutes by the process using the mercury lamp. The data clearly show that with similar total gas treatment the instant invention will produce a higher yield of product over an identical reaction time period than is produced by irradiation with the mercury lamp.

EXAMPLE 1 1 Two hundred thirty ml. of cyclohexane was treated with hydrogen chloride gas at room temperature at a flow rate of 461 ml. of hydrogen chloride per minute fora period of 20 minutes. The solution was then treated with nitrosyl chloride gas-at a flow rate of 126 ml. of nitrosyl chloride per minute together with hydrogen chloride gas at a flow rate of 461 ml. of hydrogen chloride per minute for 20 minutes. The resulting solution was sealed in a pyrex tube and the tube was exposed to the non-ionizing high intensity predominantly continuum light radiation emanating from a 50- kilowatt argon swirl-flow plasma are for 2.5 minutes by the procedure described in Example 3. After irradiation the cyclohexanone oxime was recovered as described in Example 10 and purified by sublimation. A yield of 1.69 grams of sublimed cyclohexanone oxime was obtained and its identity was confirmed by infrared analysis.

EXAMPLE 12 Two hundred thirty ml. of cyclopentane were treated with hydrogen chloride gas at room temperature at a flow rate of 461 ml. of hydrogen chloride per minute for a period of 20minutes. The solution was then treated with nitrosyl chloride gas at a flow rate of 126 ml. of nitrosyl chloride per minute together with hydrogen chloride gas at a flow rate of 461 ml. of hydrogen chloride per minute for 20 minutes. The resulting solution was sealed in a pyrex tube and the tube was exposed to the non-ionizing high intensity predominantly continuum light radiation emanating from a 50- kilowatt argon swirl-flow plasma are for 2.5 minutes by the procedure described in Example 3. After irradiation the cyclopentanone oxime was recovered as described in Example 10 and purifiedby sublimation. A yield of 1.75 grams of sublimed cyclopentanone oxime was obtained; its identity was confirmed by infrared analysis.

' EXAMPLE 13 Forty grams of cyclododecanone was placed in a pyrex tube and dissolved in 30 ml. of chlorobenzene. The resulting solution was then treated at room temperature with hydrogen chloride gas at a flow rate of 461 ml. of hydrogen chloride per minute for a period of 20 minutes. This was followed by treatment with nitrosyl chloride gas at a flow rate of 126 ml. of nitrosyl chloride per minute together with hydrogen chloride gas at a flow rate of 461 ml. of hydrogen chloride per minute for another 20 minutes. The resulting solution was subjected to irradiation for 5 minutes by exposure to the non-ionizing high intensity predominantly continuum light radiation emanating from a 50-kilowatt argon plasma are by the procedure described in Example 3. After irradiation the solution was extracted with about 150 ml. of 10 per cent hydrochloric acid. The hy- EXAMPLE 14 Pyrex tubes were charged with ml. of cyclohexane and subjected to treatment as follows:"

Tube A Air at a flow rate of 300 ml. of air per minute and sulfur dioxide at'a flow rate of 34 ml. ofsulfur dioxide per minute were passed through the cyclohexane while it was being exposed to the non-ionizing high intensity predominantly continuum light radiation emanating from a 50-kilowatt argon plasma arc. The irradiation was carried out for about 5.5 minutes by the procedure described in Example 3. After irradiation the contents were placed in a separatory funnel and water was added and shaken. The water layer was neutralized to a phenolphthalein end point with l N sodium hydroxide. The contents were again shaken and the aqueous layer again neutralized; this was repeated until the aqueous layer retained its neutral end point. At this time the layers were separated, the cyclohexane layer was washed once with water, and this aqueous extract combined with the previous aqueous fraction. The combined aqueous extracts were dried to constant weight under vacuum conditions. About 0 ml. of absolute ethanol was added per gram of dried material and the suspension was boiled, cooled and filtered. The ethanol was removed from the filtrate under reduced pressure and the residual product was dried to constant weight. The yield of cyclohexane sulfonic acid was 0.54 gram in 5.5 minutes of reaction time; its identity was confirmed by infrared spectral analysis.

Tube B The reaction was carried out as describedfor Tube A. However, the irradiation period was 2.5 hours following the procedure described in Example l and using mercury lamp ultraviolet light. The yield of cyclohexane sulfonic acid after this 2.5 hour reaction period was only 6.86 grams, which equates to 0.252 grams per 5.5 minutes.

EXAMPLE Stock solutions containing 5.6 grams of sodium bisulfite per 100 ml. of water and 4.5 grams of l-octene per 100 ml. of tert-butyl alcohol were prepared.

Seventy five ml. portions of each stock solution were placed in two pyrex tubes (Tubes I and II). In addition. 0.007 gram of Rose Bengal (Acid Red 94, Colour Index No. 45440) was placed in Tube I. The tubes were then exposed to the nonionizing high intensity predominantly continuum light radiation emanating from a 50- kilowatt plasma arc for minutes by the procedure described in Example 3. During irradiation the contents of the tubes were mixed by means of a nitrogen stream until single phase systems were obtained. After irradiation the solvents were removed by vacuum distillation and the residues dried to constant weight in a vacuum oven at 60C. The yield of crude sodium 1- octylsulfonate was 5.16 grams in Tube I and 4.03 grams in Tube 11; its identity was confirmed by infrared analy- SIS.

For comparative purposes, 150 ml. portions of each stock solution were placed in two pyrex tubes (Tubes III and IV), with 0.009 gram of Rose Bengal also present in Tube III. These tubes were irradiated by the procedure described in Example 1. It was observed that it required 15 minutes and 60 minutes to obtain a single phase system in Tubes III and IV, respectively; this compares to less than 10 and less than 15 minutes for Tubes I and II, respectively. The crude sodium 1- octylsulfonate was recovered and identified as set forth above. The yield of crude in Tube III was 12.35 grams and in Tube IV it was 10.38 grams. It is to be noted that though the yields in Tubes III and IV are about 2.4 and about 2.5 times greater than the yields in Tubes I and II, respectively, that these yields were obtained with a reaction time that is 13.5 times as long; this is an important point for commercial considerations. It was also noted that in all instances the presence of the Rose Bengal increased the yield of desired product.

What is claimed is:

1. In a photonitrosation reaction process in which a reaction mixture of a nitrosatable organic compound and a nitrosating agent is induced to react by exposure of the mixture to light suitable for the photonitrosation reaction, the improvement which comprises carrying out said process by exposing said reaction mixture to non-ionizing high intensity predominantly continuum light radiation from a swirl-flow plasma arc radiation source, said non-ionizing high intensity predominantly continuum-light radiation having a source intensity of at least 350 watts per square centimeter steradian when integrated throughout the entire spectral range of said continuum light radiation with a positive amount up to 30 per cent of the light radiated having wavelengths shorter than 4,000 A. and at least per cent but less than all of the light radiated having wavelengths longer then 4,000 A.

2. The process of claim 1, wherein the gaseous medium in the swirl-flow plasma arc is an inert rare gas.

3. The process of claim 1, wherein a photosensitizer is present in the reaction mixture during the photochemical reaction.

4. The process of claim 1, in which said reaction comprises the photonitrosation of cyclohexane with the nitrosating agent hydrogen chloride and nitrosyl chloride.

5. The process of claim 1, in which said reaction comprises the photonitrosation of cyclopentane with the nitrosating agent hydrogen chloride and nitrosyl chloride.

6. The process of claim 1, in which said reaction comprises the photonitrosation of cyclododecanone with the nitrosatingagent hydrogen chloride and nitrosyl chloride. l 

2. The process of claim 1, wherein the gaseous medium in the swirl-flow plasma arc is an inert rare gas.
 3. The process of claim 1, wherein a photosensitizer is present in the reaction mixture during the photochemical reaction.
 4. The process of claim 1, in which said reaction comprises the photonitrosation of cyclohexane with the nitrosating agent hydrogen chloride and nitrosyl chloride.
 5. The process of claim 1, in which said reaction comprises the photonitrosation of cyclopentane with the nitrosating agent hydrogen chloride and nitrosyl chloride.
 6. The process of claim 1, in which said reaction comprises the photonitrosation of cyclododecanone with the nitrosating agent hydrogen chloride and nitrosyl chloride. 